I SWEAR TO GOD THAT THERE ARE CHEATING DOGS OUT THERE WHO HAVE DOZENS OF DIFFERENT LOOKING "DOUBLE" CARDS IN THEIR BIDDING BOXES......... ( Article by Carp )

Oh yes, I'm at the end of my tether attending bridge clubs that are more in keeping with approved centers for cheating.
Time and time again I get completely stitched up by opponents who have in their bidding boxes a whole variety of " double " cards, each carrying a specific message,  which of course can only be deciphered by their partner.
You don't believe me ?  Well, allow me to convince you otherwise.
In my box I have an identical set of double cards but , strangely and bizarrely, in my opponents' bidding boxes there appears to be at least 6 different sets. For instance, their double cards can be :
- sharp edged
- crisp ( mint condition)
- flimsy, wafer thin
- thick and weighty
- faded in colour 
- dark crimson red
Obviously, each type of double card carries a clear and precise message with regards to :
- the purpose behind the bid,  be it take out or business
- the relative strength of the hand
- whether or not the bidder is well stacked in the suit doubled
- whether OR NOT that double can be pulled
So am I paranoid ?  Who knows......yet what I do know is this. Some pairs I have come across have an uncanny knack of knowing what to do after their partner doubles : when to pull it, what the best response bid should be, when to pass and convert the double into a penalty double, and what's the nature of the defensive tricks. 
In my view it had to come down to which particular double card they pulled out of the bidding box.....or may be my paranoia is causing me to miss the more obvious truth........the devious and subtle way in which the double card is placed on the table.